You might decide to sell your house without a realtor to keep control over the process and, more likely, to save money. While you'll probably get lower offers when you don't use an agent, you'll also not be paying the agent's commission. If you invest the time to prepare and market your home, you might be able to save a good amount of money.
While you are trying to save money, you will have to spend some money first. You may want to make some strategic improvements in the appearance of your home, like improving the landscaping. Also, one of the biggest tasks you'll have is advertising your home. So invest in professional-looking materials, such as an attractive, printed sign to put in your front lawn. Include brochures in an information box on the sign for people to take, as this can help weed out the less serious buyers. The brochure should include a floor plan of your house, interesting features and your asking price.
You'll also want to advertise in relevant papers and online. There are specific Web sites that are designed to help people like you sell their homes, like For Sale by Owner or the National For Sale by Owner Network. Also use your word-of-mouth network and let everyone know you're selling your house -- your friends, co-workers, doctors, hair dressers --- whoever you come into frequent contact with. You never know who knows someone who's looking.
If you are going to sell on your own, make sure understand the laws and regulations surrounding home sales. Every state will have fair housing laws and disclosure laws (these are laws that require you to disclose certain problems with your home, such as the presence of hazardous materials), and you do have to comply with them -- with or without a realtor.